The overall research objectives are the elucidation of the mechanisms by which neoplasms arise, the biochemical characterization of neoplasms as compared with their tissues of origin, the factors that regulate genetic expression in cells and viruses, the mechanisms that regulate the stages of the cell cycle, and methods for controlling or arresting the formation and growth of neoplasms. These general objectives are being fulfilled through research programs which involve studies of the induction of neoplasia and of the properties of tumors and through other programs which are directed toward an understanding of the nature of biological phenomena that appear to be of particular importance in the approach to the nature and control of neoplastic growth. The research projects of R.K. Boutwell, C. Heidelberger, E.C. Miller, and J.A. Miller are concerned with the metabolic activation of chemical carcinogens, the interactions of these activated forms with cellular constituents, and the biological and biochemical consequences of these interactions. H.M. Temin is studying the RNA tumor viruses with emphasis on their evolution and replication. Drs. B. Sugden and J.E. Mertz will develop programs on EBV and SV-40, respectively. H.C. Pitot, V.R. Potter, and J. Ross are examining mechanisms involved in the regulation of gene expression in normal and neoplastic mammalian cells. Biochemical analyses of the replication cycle and of estrogen action on mammalian cells are the focus of G.C. Mueller's research. H.P. Rusch and W.F. Dove are studying the growth and differentiation of a multinucleated organism with highly synchronous mitoses. R.R. Burgess, W.F. Dove, and W. Szybalski are examining the molecular details of transcription, the regulation of gene expression, and DNA replication. The chemistry and biochemistry of the nuclear envelope from normal and tumor cells are the focus of C.B. Kasper's research. C. Heidelberger is also continuing his development of anti-tumor and anti-viral chemotherapeutic agents.